Ugh. I was trying to say the idea of the UN. Using it wipes you out from existence as well as the target. But that doesn't happen to Galactus... who just so happens to also fear the UN... However the UN is a part of him... and he can summon it from another that would ever try to use it against him... and in fact when Quasar uses it, the energy from the UN wipes him out... but supposedly... this energy field either does not appear, or does not have the ability to affect Galactus.. yet he fears the UN.